The invention relates to a camera for picking up color pictures. The camera comprises a housing and an optical input system, a filter wheel carrying a number of filter elements, an optical distribution system and a number of pickup tubes in the housing.
The present-day color cameras usually comprises three pickup tubes. The tubes are positioned accurately with respect to an optical distribution system, for example a color-separating prism. The scene to be picked up is projected onto the windows of the pickup tubes via the optical input system and the color-separating prism. The color-separating prism separates the image of the scene into red, green and blue frames. A filter wheel carrying a number of filter elements is interposed between the optical input system and the color-separating prism. The filter elements may be, for example, gray filters, color filters or effect filters. By rotating the filter wheel, each of the filter elements can be moved into the optical path.
The filter wheel is mounted on a shaft which is driven by a gear wheel mechanism. The gear wheel mechanism is driven by an electric motor located in the housing of the camera. The size of the filter wheel is restricted by the space available in the camera.
The number of filter elements in the filter wheel is thus restricted to approximately five. This often makes it necessary to replace one filter wheel with another filter wheel, or to replace the filter elements in the filter wheel with other filter elements.
In either case the filter wheel has to be dismantled. The shaft through which the filter wheel is driven, however, is located in the interior of the camera and is not readily accessible. The result is that the replacement of the filter wheel is a laborious and time comsuming task.